Hard disk drives face severe challenges that continue to grow. The hard disk drives often comply with a form factor. The specification of a form factor dictates the external mechanical interfaces used to couple the hard disk drive to its host. These hosts may include personal entertainment systems, computers, and/or telephones that fit in a pocket of a shirt or purse and run on small batteries.
Meanwhile, the hard disk drives are often required to reliably store and access many Gigabytes (Gb) of data. These portable environments are subject to mechanical shocks, such as dropping a telephone onto a floor.
The embedded control system in a hard disk drive was often implemented as a printed circuit board positioned opposite the disk cavity and mounted on a disk base. This printed circuit board will be referred to herein as a controller printed circuit board. While the design of the controller printed circuit board was somewhat constrained by the disk drive form factor in the past, it was nonetheless a separate design task from the mechanical design of the hard disk drive.
The mechanical design of the prior art hard disk drives often included features built into the disk base to stiffen the disk base, and consequently the hard disk drive. The stiffening protected the hard disk drive from mechanical shocks such as being dropped. One commonly used feature is sometimes referred to as a rib. The rib typically ran from a spindle hub where the spindle motor shaft was positioned to an outer wall of the disk base. The disk base, particularly facing toward the controller printed circuit board, could be seen as a floor with an outer wall and a spindle hub, both rising from the floor, with the rib(s) running from the hub to the outer wall and also rising up from the floor.
Several things have changed over the last few years. A great deal of circuitry has been integrated into a few, relatively large integrated circuits. These integrated circuits have a large number of connections that the printed circuit board must provide for the hard disk drive to function.
The very small form factors for hard disk drives have forced the controller printed circuit board to impact the mechanism of the disk base, in that these integrated circuits must be accounted for in the floor plan of the disk base, making it much less possible to implement the ribs without disrupting the function of the controller printed circuit board. Somehow the hard disk drive must be configured to survive the statistically inevitable mechanical shocks, while supporting its required control functions and fitting into these very small form factors.